This application is based on Japanese Patent Application No. 11-016,699, filed on Jan. 26, 1999, the entire contents of which is hereby expressly incorporated by reference.
1. Field of the Invention
The present invention generally relates to a control for an outboard motor. More specifically, the present invention relates to an improved tiller mounted throttle and transmission control for such a motor.
2. Related Art
In order to facilitate the operation of an outboard motor, a pivotally supported handle that contains controls for operating a throttle and a transmission of the motor is attached to an end of a tiller. The handle, whether as an add-on accessory or as original equipment, offers considerable ease of operation. For instance, both the throttle and the transmission control are connected to appropriate portions of the outboard motor such that the throttle controls the engine speed and the transmission control controls the engagement of the transmission. Accordingly, the controls are arranged conveniently close to each other.
U.S. Pat. No. 5,545,064, issued to Tsunekawa et al., disclosed a shift interlock that sought to prevent the operator from shifting the transmission into neutral (i.e., from forward to neutral, reverse to neutral, etc.) when the engine was operating at a high rate of speed. As disclosed therein, attempting such transmission shifts when the engine was running at a high rate of speed not only placed large loads on the clutch and gear mechanism of the transmission, but also could have caused sudden changes in watercraft movement that might have been disconcerting to its occupants.
With reference now to FIG. 1, a perspective view of a transmission-throttle interlock mechanism is illustrated therein. The illustrated interlock 10 is similar in some respects to that illustrated in FIG. 11 of U.S. Pat. No. 5,545,064. As illustrated, the interlock 10 generally comprises a cam 12 and a cam plate 14 that are brought into engagement under select conditions. The cam 12 is attached to a throttle control shaft 16 that is rotated to increase engine speed. As the illustrated throttle control shaft 16 is rotated in a counterclockwise manner, the cam 12 is rotated toward the cam plate 14. The cam plate 14 is attached to a transmission shift lever 18 in any suitable manner. As the transmission shift lever 18 is moved between positions that correspond to positions for forward, reverse and neutral gear selections (indicated by arrow and F, R and N designations), the cam plate 14 is moved with the lever. When the transmission is positioned in the neutral position, the cam plate 14 limits the range of movement of the throttle control shaft 16 using a stopping surface 20 and when the transmission is positioned in the drive or reverse positions, the cam 12 does not contact the illustrated cam plate. Thus, the interaction of the cam 12 and the stopping surface of the cam plate 14 limit the speed at which the engine can be run with the engine in the neutral position but not in the drive or reverse positions.
The illustrated interlock 10, however, suffers from at least one drawback. While the interlock 10 limits engine speed when the transmission is in the neutral position, the interlock 10 does not regulate shift operation. For instance, if the engine speed is high enough, the interlock does not prevent movement of the transmission shift lever from a drive condition into the neutral position. In fact, in the illustrated arrangement, such a movement of the transmission shift lever could result in the throttle being stuck in a high speed position until the transmission is again shifted into a drive position and the throttle angle is decreased. In addition, the illustrated interlock allows the transmission to be slid into gear from the neutral position even with the throttle cam pegged against the stopping surface. Thus, a shift interlock is desired that would limit shifting to conditions. For instance, engine speed should be decreased before shifting is undertaken.
Accordingly, one aspect of the present invention involves an outboard motor comprising a tiller and a handle that is connected to the tiller and that comprises a housing. A throttle control shaft extends generally longitudinally through the housing and rotates about a generally longitudinally extending rotational axis. A cam is repositionably secured to the shaft. A transmission control lever is pivotally attached to the housing with the lever pivoting about a generally transverse axis. A cam plate is fixed to the lever for pivotal movement with the lever. The cam plate includes a pair of generally parallel ribs and a stopping surface that is interposed between the ribs. The cam and the stopping surface are arranged to contact when the shaft is in a first preselected angular shaft position and the transmission control lever is in a first preselected transmission position. The cam is secured in position between the ribs when the shaft is in the first preselected angular shaft position such that the cam plate and the lever are held in the first preselected transmission position.
Another aspect of the present invention involves an outboard motor tiller control comprising a handle housing assembly adapted to be attached to a tiller of an outboard motor. A throttle control shaft is journaled within the housing for rotation about a generally longitudinally extending rotational axis and a transmission shifting control lever is supported for pivotal movement relative to the handle housing assembly about a generally transversely extending pivot axis. Means are provided for selectively interlocking the shifting control lever and the throttle control shaft such that the shifting control lever is locked in a first preselected pivotal position when the throttle control shaft is rotated to a first preselected angular position.
A further aspect of the present invention involves an outboard motor tiller control comprising a handle housing assembly adapted to be attached to a tiller of an outboard motor. A throttle control shaft is journaled within the housing for rotation about a generally longitudinally extending rotational axis and a transmission shifting control lever is supported for pivotal movement relative to the handle housing assembly about a generally transversely extending pivot axis. A means is provided for selectively interlocking the shifting control lever and the throttle control shaft such that the shifting control lever is locked out of a first preselected pivotal position when the throttle control shaft is rotated to a first preselected angular position.